Comparing Web Traffic Between Different Web Analytictical Tools

Comparing ones Web traffic to an other's Web traffic when those two sites/servers run different Web analytical tools is like comparing Apples to Oranges. It is just not possible to accurately compare the two.

For example, around November and December of 2003 I upgraded to Urchin 5.5 Web analytics from Urchin 3 Web analytics. The way those two software looked at traffic was drastically different. My traffic server wide dropped about 75% due to the enhanced technology in the new Urchin 5.5 to more accurately track a visitor. See the chart below. The traffic on the left was from Urchin 3.0 versus the traffic on the right which is when the new Urchin 5.5 was installed on my server.